FreescaleMK30X256单相电表参考设计方案
Kinetis K30 Family Low-power MCUs with segment LCD
The Kinetis MCU portfolio consists of multiple pin-, peripheral- and software-compatible MCU families based on the ARM Cortex™-M4 core.
Families are built from innovative 90 nm thinfilm storage (TFS) flash technology with unique FlexMemory (EEPROM) capability, and offer industry-leading low power and mixed signal analog integration.
The K30 MCU family is pin-, peripheral- and software-compatible with the K10 MCU family and adds a flexible low-power segment LCD controller with support for up to 320 segments. Devices start from 64 KB of flash in 64 QFN packages extending up to 512 KB in a 144 MAPBGA package with a rich suite of analog, communication, timing and control peripherals.
K30 MCU主要特性:
• Operating Characteristics
– Voltage range: 1.71 to 3.6 V
– Flash write voltage range: 1.71 to 3.6 V
– Temperature range (ambient): -40 to 105°C
• Performance Up to 100 MHz ARM Cortex-M4 core with DSP instructions delivering 1.25 Dhrystone MIPS per MHz
• Memories and memory interfaces
– Up to 512 KB program flash memory on non- FlexMemory devices
– Up to 128 KB RAM
– Serial programming interface (EzPort)
• Clocks
– 3 to 32 MHz crystal oscillator
– 32 kHz crystal oscillator
– Multi-purpose clock generator
• System peripherals
– 10 low-power modes to provide power optimization based on application requirements
– Memory protection unit with multi-master protection
– 16-channel DMA controller, supporting up to 64 request sources
– External watchdog monitor
– Software watchdog
– Low-leakage wakeup unit
• Security and integrity modules
– Hardware CRC module to support fast cyclic redundancy checks
– 128-bit unique identification (ID) number per chip
• Human-machine interface
Segment LCD controller supporting up to 40 frontplanes and 8 backplanes, or 44 frontplanes and 4 backplanes
– Low-power hardware touch sensor interface (TSI)
– General-purpose input/output
• Analog modules
– Two 16-bit SAR ADCs
– Programmable gain amplifier (PGA) (up to x64) integrated into each ADC
– 12-bit DAC
– Three analog comparators (CMP) containing a 6-bit DAC and programmable reference input
– Voltage reference
• Timers
– Programmable delay block
– Eight-channel motor control/general purpose/PWM timer
– Two 2-channel quadrature decoder/general purpose timers
– Periodic interrupt timers
– 16-bit low-power timer
– Carrier modulator transmitter
– Real-time clock
• Communication interfaces
– Controller Area Network (CAN) module
– Two SPI modules
– Two I2C modules
– Four UART modules
– Secure Digital host controller (SDHC) I2S module
K30 MCU特性和优势:
K30 MCU典型应用:
• Thermostats
• Smart meters
• Heart rate monitors
• Blood gas analyzer
图1.K30 MCU系列方框图
MQXTM + ZigBee® MK30X256单相电表参考设计
MQX-Based Kinetis (MK30X256) Single-Phase Electricity Meter Reference Design
The reference design provides a highperformance solution for power measurement in single phase two wire installations. The target market is residential metering. The reference design has the ability to connect to a ZigBee® network through an internal Daughter Card.
Hence, it can easily become part of the Smart Grid network. Firmware for this reference design is based on the MQXTM real time operating system - designed for usage in advanced markets. All standard metering values are displayed on the built-in LCD. The user can choose one of these values by clicking the built-in button. For remote data collecting, there are several types of communication interfaces.
MK30X256单相电表参考设计主要特性:
• 5(60)A current range, nominal current is 5A, peak current is 60A
• 85V...264V voltage range
• 47Hz...63Hz frequency range
• 4-quadrant measurement
• Active and reactive energy accuracy:IEC50470-3 Class B, 1%
• Meter constants (imp/kWh, imp/kVArh):500, 1000, 2000, 5000, 10000
• Line frequency measurement (for precision zero-cross detection)
• Cost-effective shunt resistor sensing circuit implementation
• Cost-effective bill of materials (BOM)
• Low-power modes effectively implemented, including the use of the built-in RTC (Libattery backed-up)
• LCD display, 4x31 segments including charge pump
• Values shown on the LCD: V,A,W,VAr,VA, kWh, kVArh, cos j, Hz, time, date
• OBIS identifier on the LCD
• Tamper detection via two tamper buttons or magnetometer (event is stored in memory)
• Built-in user push-button
• LED pulse outputs (kWh, kVArh)
• Optically-isolated open-collector output
• IEC1107 infrared hardware interface
• Optically isolated RS232 interface
• 2.4 GHz RF 1322x interface (I2C Daughter Card) for connection to a ZigBee® network
• MQXTM based for advanced markets
• Multiple advanced metering algorithms (FFT, filter-based method)
Product Features and Specifications
• Design Reference Manual (DRM122)
• AN4255 - FFT-based algorithm for metering applications
• Quick Start for MK30XEMETER
• MQX Reference Manual and MQX User’s Guide
• 1322x Low-Power Node Reference Manual
• Device development tools / demo kits:
MK30XEMETER_xxxx
• Device documentation: MK30X256
图2.MK30X256单相电表参考设计外形图
图3.MK30X256单相电表方框图
电表主要指标:
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